There have been many different types of intraocular lens anchoring systems for positioning the optical portion of the lens in the desired location within the eye. One type of anchoring system is described in the Richards et al U.S. Pat. Nos. 3,975,779 and 4,014,049. In these patents, an optical lens is held in position by a series of outwardly biased iris clips that are designed to expand and contract as the iris dilates and contracts.
Another type of intraocular lens positioning structure is described in the Lieb U.S. Pat. No. 2,834,023. The optical lens 20 of this patent is held in place by a pair of opposed closed loops 22 that do not connect directly to the iris. Instead, these loops 22 press outwardly against the eye's anatomy at the peripheral base of the cornea area in front of the iris. As shown in FIG. 2 of this patent, the optical lens portion 20 is in the anterior chamber of the eye.
A similar type lens in the posterior chamber is described in the Shearing U.S. Pat. No. 4,159,546. Here the optical lens 12 is held in position by a pair of J-shaped members 14 and 16 which have their outer ends curved or blunted to avoid gouging into the ciliary sulcus region of the eye directly behind the iris.
All of the above type anchoring systems for holding the optical section of the intraocular lens in position have a common problem. This problem deals with the limited flexibility of the loop or retaining structure that is outwardly urged against the eye. These eye engaging loops, prongs, etc. must be made stiff enough so as not to collapse under continual compression over the several years that the intraocular lens is likely to be within the eye. However, if the retaining structures are too stiff, excessive outward pressure against the iris (iris clip), ciliary sulcus region (posterior chamber), or peripheral base of the cornea (anterior chamber) could cause some deterioration of tissue within such area of the eye over a period of time.